Corvette C5 8,800 miles on oil.

[buster]

http://forums.corvetteforum.com/zerothread?id=668098


2001 Vette with consumption problem. Mobil 1 5w30. Driven very hard and mostly city driving. Not bad results at all. 3qts of make up oil though.

BTW, the link works but this website has been having server problems. It should be up soon.

[ October 09, 2003, 09:42 PM: Message edited by: buster ]

 

[Patman]

In case the server goes down, I'll type up the results here:

Mobil 1 5w30
8719 miles on oil/24157 on engine


Aluminum-2
Chromium-2
Iron-29
Copper-68
Lead-8
Tin-2
Moly-66
Nickel-1
Manganese-1
Silver-0
Titanium-0
Potassium-0
Boron-115
Silicon-8 (very nice!)
Sodium-9
Calcium-3341
Magnesium-27
Phos-757
Zinc-858
Barium-0
Viscosity-68.0 (which is 12.4, almost 40wt)
Fuel, Water, Glycol-0
Insolubles-0.3
TBN-5.0


All in all this oil did a great job here, lead is very nice for a car that is driven hard. I'm sure the thicker viscosity of this oil helped out immensely here.

I wonder if this is the newest version of this oil, I see this has higher calcium like the newest formulations have, but Boron isn't as high though.

The 3qts of makeup oil definitely skews the numbers to being more favorable though.

Like I've mentioned here before, the low tension rings that they used in the 2001 version of the LS1 are responsible for this model year burning a lot more oil than the rest.

[ October 10, 2003, 04:51 AM: Message edited by: Patman ]

 

[sbc350gearhead]

I though you couldn't run low tension rings without a vacuum pump?

 

[buster]

bror, the car was driven very hard and the oil is still a 30wt, barely but still a 30wt. Consumption is not the oils fault, it's a 2001 with the notorious consumption problem. However, Amsoil still is a better choice in this engine because it starts out thicker. For all we know the thickening could have actaully helped wear in this case.

 

[TooSlick]

Bror,

Oxidation and Nitration are both accelerated by high heat, so oxidative thickening is common in an vehicle that is driven hard like this one. A fairly high solids level, given the 3 qts of makeup oil ....

TS

 

[Bror Jace]

The oil thickened in that short span of time? Could that be caused by oxidation? I wonder if the 10W30 would hold up better (be more stable) over the lonfer term? It might also cut down on consumption. Also, for summer driving, I'd even be tempted to throw a quart of 15W50 into the mix.

*Note, I'm not suggesting the owner needs to switch brands.

I know wear is relatively low, and ultimately that's what matters most, but if I had a 'vette, I think I'd change the oil & filter every 2,500-3,000 out of pure obsessive-compulsive-anal-retentive-euphoria.

Extended drains on even a semi-exotic car seem penny wise and pound foolish.

--- Bror Jace

 

[Bror Jace]

buster, I wasn't aware of the consumption problems of this engine.

Tooslick, That's pretty much what I figured.

I wonder if the 10W30 would have held up better? Once the oil begins to oxidize and thicken, its lubricating properties diminish (say, coefficient of friction). This oil must've taken some beating to thin it out and then thicken it up again like that.

I think the make-up oil helped this sample a lot ... but then again if it were my ride the interval would have been only about a third of this car's ... and the make-up oil I would have had to add would probably be about a third as well.

--- Bror Jace

 

[buster]

bror, I do think the 10w30 would have held it's grade better. Mobil 1 10w30 is one of the most shear stable oils you can buy. TS's thread the other day shows this. Make up oil definitely helps but considering the driving was very hard, it still did a nice job. As Patman always has said though, a thicker oil such as Amsoil does seem to show better wear numbers in this engine.

 

[chadwick]

This is actually my C5 referenced in the first post.

Once piece of data I left out over there was time: the oil was in use from December 2002 until September of 2003. Most of the miles came in the last half of that time period.

The main reason I did this particular analysis was to see how the C5's oil life monitor compared to analysis of the oil after the fact. Given the analysis data, and that the OLM said 5% life remaining, they seem pretty consistent with one another. It's an ongoing argument (everywhere I'm sure) on if the OLM can be trusted or not. For one reason or another, this was the first oil change where I was actually able to let it go all the way.

I'll do what the lab suggested and get another sample at 5K miles this time. It will be interesting to see how they will compare. My usage rate seems to be the same as last time, so I would expect 40-45% oil life remaining at the 5K mark this time.

Believe it or not, GM says my oil consumption is normal and within proper limits.

 

[buster]

chadwick, thanks for the post! It's always good to look at these reports.

 

[Bror Jace]

"Believe it or not, GM says my oil consumption is normal and within proper limits."

They would say that even if you were using a quart every 1,000 miles.

I think your cutting down on the interval is wise ... and the extra expense is negligible when comparing what it costs to keep a 'vette on the road these days.

--- Bror Jace

 

[williar]

With the consumption you have, why not use a conventional 10w30 oil and change it every 3K? I'll bet you'll burn half the oil.

 

[Patman]

quote:

---

Originally posted by williar:
With the consumption you have, why not use a conventional 10w30 oil and change it every 3K? I'll bet you'll burn half the oil.

---

C5 Corvettes require synthetic oil to keep their warranty though. And with the 300 degree oil temps these engines can see under road racing and similar sustained hard driving, I wouldn't even attempt to run a conventional oil in this engine.

The only real fix for the oil consumption is to get new piston rings put in, because as I mentioned, the 2001 design just isn't very good.